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Soft tissue management in total hip arthroplasty includes appropriate restoration and/or alteration of leg length (LL) and offset to re-establish natural hip biomechanics. The purpose of this study was to evaluate the effect of LL and offset-derived variables in a multivariable survival model for dislocation. Clinical, surgical, and radiographic data was retrospectively acquired for 12,582 patients undergoing primary total hip arthroplasty at a single institution from 1998 to 2018. There were twelve variables derived from preoperative and postoperative radiographs related to LL and offset that were measured using a validated automated algorithm. These measurements, as well as other modifiable and nonmodifiable surgical, clinical, and demographic factors, were used to determine hazard ratios for dislocation risk. None of the LL or offset variables conferred significant risk or protective benefit for dislocation risk. By contrast, all other variables included in the multivariable model demonstrated a statistically significant effect on dislocation risk with a minimum effect size of 28% (range 0.72 to 1.54) (sex, surgical approach, acetabular liner type, femoral head size, neurologic disease, spine disease, and prior spine surgery). Contrary to traditional teaching and our hypothesis, operative changes in LL and offset did not demonstrate any clinically or statistically significant effect in this large and well-characterized cohort. This does not imply that these variables are not important in individual cases, but rather suggests the overall impact of LL and offset changes is relatively minor for dislocation risk compared to other variables that were found to be highly clinically and statistically significant in this population. These results may also suggest that surgeons do a good job of restoring native LL and offset for patients, which may mitigate their analyzed impact. [ABSTRACT FROM AUTHOR]

There is a paucity of data beyond 15 years on the survivorship of total hip arthroplasty since the introduction of highly cross-linked polyethylene (HXLPE) liners. Our aim was to evaluate implant survivorship, liner wear rates, and clinical outcomes after primary total hip arthroplasty using HXLPE liners implanted between 1999 and 2002. Between 1999 and 2002, 690 primary total hip arthroplasties utilizing 28-mm femoral heads and HXLPE liners of a single design were identified using our institutional total joint registry. Femoral heads were made of metal in 96% of cases and ceramic in 4%. The mean age was 56 years, 48% were women, and the mean body mass index was 30. Survivorship analyses were performed for the outcomes of implant revision, reoperation, and complications for the entire cohort. Linear HXLPE liner wear rates were determined on 197 hips with radiographs with more than 18.5 years of follow-up. At 20 years, survivorship free of revision was 94%, free of reoperation was 92%, and free of any complication was 81%. There were no documented wear-related revisions. The linear wear rate at a mean of 20.3 years postoperatively was 0.02 mm/y. There was no statistically significant difference in measured wear observed between the first available postoperative radiographs and those taken at the final follow-up. The use of elevated liners, patient body mass index, age, preoperative diagnosis, acetabular component inclination, and anteversion angles were not associated with increased wear rates. Mean Harris hip scores improved from 52 preoperatively to 90 at greater than 18.5 years Primary total hip arthroplasties using a single first-generation HXLPE liner demonstrated excellent survivorship and clinical outcomes at long-term follow-up with no wear-related revisions. Wear rates of HXLPE liners at 20 years are exceedingly low and are not significantly impacted by acetabular component position or patient-dependent variables such as BMI. IV [ABSTRACT FROM AUTHOR]

Our previously reported randomized clinical trial of direct anterior approach (DAA) versus mini-posterior approach (MPA) total hip arthroplasty showed slightly faster initial recovery for patients who had a DAA and no differences in complications or clinical or radiographic outcomes beyond 8 weeks. The aims of the current study were to determine if early advantages of DAA led to meaningful clinical differences beyond 5 years and to identify differences in midterm complications. Of the 101 original patients, 93 were eligible for follow-up at a mean of 7.5 years (range, 2.1 to 10). Clinical outcomes were compared with Harris Hip, 12-Item Short Form Health Survey, and Hip Disability and Osteoarthritis Outcomes Scores (HOOS) scores and subscores, complications, reoperations, and revisions. Harris Hip scores were similar (95.3 ± 6.0 versus 93.5 ± 10.3 for DAA and MPA, respectively, P =.79). The 12-Item Short Form Health Survey physical and mental scores were similar (46.2 ± 9.3 versus 46.2 ± 10.6, P =.79, and 52.3 ± 7.1 versus 55.2 ± 4.5, P =.07 in the DAA and MPA groups, respectively). The HOOS scores were similar (97.4 ± 7.9 versus 96.3 ± 6.7 for DAA and MPA, respectively, P =.07). The HOOS quality of life subscores were 96.9 ± 10.8 versus 92.3 ± 16.0 for DAA and MPA, respectively (P =.046). No clinical outcome met the minimally clinically important difference. There were 4 surgical complications in the DAA group (1 femoral loosening requiring revision, 1 dislocation treated closed, and 2 wound dehiscences requiring debridement), and 6 surgical complications in the MPA group (3 dislocations, 2 treated closed, and 1 revised to dual mobility; 2 intraoperative fractures treated with a cable; and 1 wound dehiscence treated nonoperatively). At a mean of 7.5 years, this randomized clinical trial demonstrated no clinically meaningful differences in outcomes, complications, reoperations, or revisions between DAA and MPA total hip arthroplasty. IV. [ABSTRACT FROM AUTHOR]

Porous tantalum acetabular cup and augment constructs have demonstrated favorable outcomes up to 5 years postsurgery despite severe bone loss during revision total hip arthroplasty (THA). Prior literature lacks long-term studies with substantial case numbers. This study aims to assess long-term clinical and radiographic outcomes 10 years postsurgery in patients undergoing revision THA with porous tantalum acetabular cup-augment constructs and determine factors associated with long-term survivorship. Between 2000 and 2012, 157 revision THAs were performed in cases with major acetabular defects (mainly Paprosky type IIIA and IIIB) utilizing porous tantalum cup-augment constructs. Pelvic discontinuity was noted intraoperatively in 17 hips (11%). Postoperative radiographs were evaluated at regular intervals for implant stability and radiolucent lines. There were 49 patients who had complete radiographic follow-up at 10 years or longer postsurgery. The 10-year survivorship free of revision of the cup-augment construct for aseptic loosening was 93%, free of any acetabular construct revision was 91%, free of any hip rerevision was 77%, and free of any reoperation was 75%. Pelvic discontinuity was associated with increased risk of reoperation (hazard ratio [HR] = 2.8), any hip rerevision (HR = 3.2), any cup-augment construct revision (HR = 11.8), and aseptic construct revision (HR = 10.0). Of unrevised cases with radiographs at 10 years, 4 hips showed radiographic loosening. Mean Harris hip scores improved from 47 preoperatively to 79 at 10 years. Porous tantalum acetabular cup-augment constructs used in revision THA with severe acetabular bone loss provide excellent implant survivorship at 10 years when the acetabulum is intact. Due to lower survivorship of cup-augment constructs in cases of pelvic discontinuity, additional construct fixation or stabilization methods are recommended, when a discontinuity is present. IV [ABSTRACT FROM AUTHOR]

Intraprosthetic dissociation (IPD) is a complication unique to dual mobility (DM) implants where the outer polyethylene head dissociates from the inner femoral head. Increasing reports of IPD at the time of closed reduction of large head DM dislocations prompted this biomechanical study evaluating the assembly and dissociation forces of DM heads. We tested 17 polyethylene DM heads from 5 vendors. Of the heads, 12 were highly cross-linked polyethylene (4 vendors) and 5 were infused with vitamin E (2 vendors). Heads were between 46 and 47 mm in diameter, accepting a 28 mm-inner ceramic head. Implants were assembled and disassembled using a servohydraulic machine that recorded the forces and torques applied during testing. Dissociation was tested via both axial pull-out and lever-out techniques, where lever-out simulated stem-on-acetabular component impingement. The initial maximum assembly force was significantly different between all vendors (P <.01) and decreased for all implants with subsequent assembly. Vendor 4-E (Link with vitamin E) heads required the highest assembly force (1,831.9 ± 81.95 N), followed by Vendor 3 (Smith & Nephew), Vendor 5 (DePuy Synthes), Vendor 1-E (Zimmer Biomet with vitamin E), Vendor 2 (Stryker), and Vendor 1 (Zimmer Biomet Arcom). Vendor 4-E implants showed the greatest dissociation resistance in both pull-out (2,059.89 N, n = 1) and lever-out (38.95 ± 2.79 Nm) tests. Vendor 1-E implants with vitamin E required higher assembly force, dissociation force, and energy than Vendor 1 heads without vitamin E. There were notable differences in DM assembly and dissociation forces between implants. Diminishing force was required for assembly with each additional trial across vendors. Vendor 4-E DM heads required the highest assembly and dissociation forces. Vitamin E appeared to increase the assembly and dissociation forces. Based on these results, DM polyethylene heads should not be reimplanted after dissociation, and there may be a role for establishing a minimum dissociation energy standard to minimize IPD risk. [ABSTRACT FROM AUTHOR]

Femur-first (FF) technique for mobile-bearing medial unicompartmental knee arthroplasty (UKA) has been described as an alternative to tibia-first (TF) technique. The aim of this study was to compare the radiographic results in UKAs using FF or TF techniques and their influence on failure rates. We retrospectively reviewed 288 UKAs with a minimum 2-year follow-up. There were 147 knees in the TF and 141 knees in the FF cohorts. Alignment parameters and overhang were assessed as outliers and far outliers. The mean follow-up was 6 years (range, 2 to 16), the mean age was 63 years (range, 27 to 92), and 45% of patients were women. Univariate and multivariate statistical analyses were carried out with Cox regression models. There were 13 and 6 revisions in the TF and FF cohorts, respectively. The FF had lower rates of femoral coronal alignment (FCA) or femoral sagittal alignment outliers compared to the TF (5.7% versus 19%, P =.011). Tibial coronal alignment and tibial sagittal alignment did not significantly differ between the techniques (22.7% in FF versus 29.9% in TF, P =.119). Overhang outliers did not differ significantly between the groups. Younger age was associated with a higher revision rate (P =.006), while FF versus TF, sex, body mass index, and postoperative mechanical axis did not show statistically significant associations. In multivariate analysis, FCA outliers and younger age were significantly associated with revision. The FF technique in mobile-bearing UKA resulted in fewer FCA outliers compared to TF. Despite improved knee alignment with the FF technique, FCA outliers and younger age were associated with a higher revision rate, independent of technique. [ABSTRACT FROM AUTHOR]

Registry data have demonstrated lower rates of revision and periprosthetic fracture in select cohorts with cemented femoral fixation at primary total hip arthroplasty. Whether this is true of all component designs is not known. We hypothesized that selected use of ream-and-broach triple-tapered uncemented stem designs may provide comparable results to cemented stems. From 2000 to 2018, 5,809 primary total hip arthroplasties were performed with either a cemented (1,304) or ream-and-broach triple-tapered uncemented stem (4,505). Implant choice was at surgeon discretion. The cemented group was older, more often women, and had slightly lower body mass index. A subgroup analysis was performed on patients ≥75 years of age. Statistical weighting accounted for baseline cohort differences. At 10 years, there was a trend toward higher all-cause revision (hazards ratio (HR) 1.6, P =.053) and higher all-cause reoperation (HR 1.6, P =.02) in the cemented fixation cohort. The cemented fixation group had fewer intraoperative periprosthetic fractures (HR 0.21, P <.001) but no difference in postoperative fractures (HR 0.99, P =.96). The same was true in patients ≥75 years. In the ≥75-years subgroup, there was no difference in revision or reoperation at 10 years. Compared to cemented stems, the use of ream-and-broach triple-tapered uncemented stems in select patients, including those ≥75 years, was associated with more intraoperative fractures but no difference in 10-year implant survivorship. These findings are different than some registry data and suggest that specific uncemented components, implanted in selected patients by experienced surgeons, can perform as well as cemented implants in a broad patient population. [ABSTRACT FROM AUTHOR]

The advent of highly porous ingrowth surfaces and highly crosslinked polyethylene has been expected to improve implant survivorship in revision total hip arthroplasty. Therefore, we sought to evaluate the survival of several contemporary acetabular designs following revision total hip arthroplasty. Acetabular revisions performed from 2000 to 2019 were identified from our institutional total joint registry. We studied 3,348 revision hips, implanted with 1 of 7 cementless acetabular designs. These were paired with highly crosslinked polyethylene or dual-mobility liners. A historical series of 258 Harris-Galante-1 components, paired with conventional polyethylene, was used as reference. Survivorship analyses were performed. For the 2,976 hips with minimum 2-year follow-up, the median follow-up was 8 years (range, 2 to 35 years). Contemporary components with adequate follow-up had survivorship free of acetabular rerevision of ≥95% at 10-year follow-up. Relative to Harris-Galante-1 components, 10-year survivorship free of all-cause acetabular cup rerevision was significantly higher in Zimmer Trabecular Metarevision (hazard ratio (HR) 0.3, 95% confidence interval (CI) 0.2-0.45), Zimmer Trabecular MetaModular (HR 0.34, 95% CI 0.13-0.89), Zimmer Trilogy (HR 0.4, 95% CI 0.24-0.69), DePuy Pinnacle Porocoat (HR 0.24, 95% CI 0.11-0.51), and Stryker Tritanium revision (HR 0.46, 95% CI 0.24-0.91) shells. Among contemporary components, there were only 23 rerevisions for acetabular aseptic loosening and no rerevisions for polyethylene wear. Contemporary acetabular ingrowth and bearing surfaces were associated with no rerevisions for wear and aseptic loosening was uncommon, particularly with highly porous designs. Therefore, it appears that contemporary revision acetabular components have dramatically improved upon historical results at available follow-up. [ABSTRACT FROM AUTHOR]

Many risk factors have been described for periprosthetic femur fracture (PPFFx) following total hip arthroplasty (THA), yet a patient-specific risk assessment tool remains elusive. The purpose of this study was to develop a high-dimensional, patient-specific risk-stratification nomogram that allows dynamic risk modification based on operative decisions. We evaluated 16,696 primary nononcologic THAs performed between 1998 and 2018. During a mean 6-year follow-up, 558 patients (3.3%) sustained a PPFFx. Patients were characterized by individual natural language processing-assisted chart review on nonmodifiable factors (demographics, THA indication, and comorbidities), and modifiable operative decisions (femoral fixation [cemented/uncemented], surgical approach [direct anterior, lateral, and posterior], and implant type [collared/collarless]). Multivariable Cox regression models and nomograms were developed with PPFFx as a binary outcome at 90 days, 1 year, and 5 years, postoperatively. Patient-specific PPFFx risk based on comorbid profile was wide-ranging from 0.4-18% at 90 days, 0.4%-20% at 1 year, and 0.5%-25% at 5 years. Among 18 evaluated patient factors, 7 were retained in multivariable analyses. The 4 significant nonmodifiable factors included the following: women (hazard ratio (HR) = 1.6), older age (HR = 1.2 per 10 years), diagnosis of osteoporosis or use of osteoporosis medications (HR = 1.7), and indication for surgery other than osteoarthritis (HR = 2.2 for fracture, HR = 1.8 for inflammatory arthritis, HR = 1.7 for osteonecrosis). The 3 modifiable surgical factors were included as follows: uncemented femoral fixation (HR = 2.5), collarless femoral implants (HR = 1.3), and surgical approach other than direct anterior (lateral HR = 2.9, posterior HR = 1.9). This patient-specific PPFFx risk calculator demonstrated a wide-ranging risk based on comorbid profile and enables surgeons to quantify risk mitigation based on operative decisions. Level III, Prognostic. [ABSTRACT FROM AUTHOR]

Higher failure rates of unicompartmental knee arthroplasty (UKA) are seen with lower surgical volume. Surgical techniques that introduce less variability improving implant positioning may lead to improved survivorship. A femur-first (FF) technique has been described, but survivorship data compared to traditional tibia-first (TF) technique are under-reported. We report the results of mobile-bearing UKA using the FF technique compared to the TF technique with emphasis on implant position and survivorship. A total of 430 UKAs were performed by a single surgeon between 2007 and 2020. After 2012, there were 141 consecutive UKAs performed with the FF technique which were compared with 147 consecutive UKAs prior. Mean follow-up was 6 years (range, 2 to 13 years), average age was 63 years (range, 23 to 92 years), and there were 132 women. Postoperative radiographs were reviewed to determine implant positioning. Survivorship analyses were performed using Kaplan-Meier curves. The FF resulted in significantly thinner polyethylene (3.4 ± 0.7 mm versus 3.7 ± 0.9 mm) (P =.002) and 4 mm or less bearing thickness in 94% of cases. At 5 years, there was an early trend toward improved survivorship free from component revision (98% for the FF group and 94% for the TF [ P =.35]). The FF cohort had higher Knee Society Functional scores at final follow-up (P <.001). Compared to traditional TF technique, the FF was more bone-preserving and improved radiographic positioning. The FF technique is an alternative method for mobile-bearing UKA and was associated with an improvement in implant survivorship and function. [ABSTRACT FROM AUTHOR]

Background: Cemented femoral components are used in older patients based on lower risk of periprosthetic fracture and implant loosening. This study reports the survivorship free of periprosthetic femoral fracture (PPFX), femoral loosening, all-cause revision, and reoperation between 2 philosophies of cemented stems.Methods: In total, 1,306 primary hybrid total hip arthroplasties were performed for osteoarthritis between 2000 and 2018 in a retrospective single center study. Cemented stems included 798 EON composite beam (CB) and 508 Exeter collarless taper slip (CTS) stems. Mean age was 77 years. An inverse treated probability weighted model was utilized to control for risk factors including age, gender, body mass index, year, and surgeon.Results: There was no difference in risk of PPFX at 10 years (CTS 9% vs CB 5%; hazard ratio [HR] 1.4, P = .47). There was an increased risk of intraoperative fractures requiring fixation in the CB cohort (7/798 [5 calcar, 2 greater trochanter] vs 0/508, P < .001), while there was an increased risk of Vancouver B2 PPFX in the CTS cohort (7/508 vs 0/798; P < 001). There was a higher risk of femoral loosening in the CB cohort (6/798 vs 0/508; P < .0001). Higher survivorship free of revision (98% vs 91%; HR 4, P = .001) and free of reoperation (96% vs 88%; HR 2.5, P = .002) was seen at 10 years in the CB cohort.Conclusion: The risk of PPFX requiring implant revision was increased in the CTS cohort, while there was an increased risk of femoral component loosening and intraoperative fractures seen in the CB cohort. Surgeons should be aware of the different failure modes when choosing implant design for their patient. [ABSTRACT FROM AUTHOR]

Background: Mobile-bearing unicompartmental knee arthroplasty (UKA) provides a durable option for the surgical treatment of monocompartmental knee arthritis. Despite its availability in the United States since 2004, there is only 1 published North American series reporting on the minimum 10-year results of mobile-bearing UKA. The purpose of this study is to determine the survivorship, reasons for failure, and patient-reported outcomes of the Oxford mobile-bearing UKA at minimum 10-year follow-up.Methods: One hundred fifty-seven knees were eligible for inclusion in this study based on the date of their index surgery allowing for a minimum 10-year follow-up. The mean follow-up from implantation was 11.4 years (range 10.0-13.8). Failures were reviewed for potential etiologic factors. Survivorship free of reoperation for any reason and free of revision was determined using Kaplan-Meier curves. Functional outcomes were assessed using the Knee Society Knee and Function scores.Results: There were 17 revisions (10.6%). Six were secondary to progression of lateral compartment arthritis, 5 for persistent pain, 3 for femoral component aseptic loosening, 2 polyethylene dislocations, and 1 deep infection. The mean time to revision was 4 years (range 0.1-11). The survivorship free from revision at minimum 10-year follow-up was 85%. At final follow-up, the mean Knee Society Knee Score was 93 (range 66-100) and the mean functional score was 80 (range 30-100).Conclusion: This single surgeon series demonstrated a survivorship of 85% at minimum 10-year follow-up. These results are comparable to published data from North America, but survivorship is lower than European series. [ABSTRACT FROM AUTHOR]

Background: Osteogenesis imperfecta (OI) comprises a spectrum of disorders that result in bone fragility. This presents unique challenges when performing total joint arthroplasty in patients with OI. The purpose of this study is to determine the survivorship and clinical outcomes of total hip arthroplasty (THA) in patients with OI.Methods: We retrospectively reviewed our institution's total joint registry from 1969 to 2018 for all primary THAs in patients with a history of OI. There were 11 patients (13 hips) with a mean follow-up of 13 years (range 6-20). Survivorship free of component revision was determined using Kaplan-Meier analysis. Patient-reported clinical outcomes were assessed using Harris Hip Scores.Results: At final follow-up, the status of the implant was known in all 13 hips. One patient (1 hip) was deceased. Four hips (31%) underwent revision surgery at a mean of 9 years (range 5-17). Survivorship free of component revision was 52% at 20 years. Mean Harris Hip Scores at final follow-up were fair (75, 47-97), but significantly improved compared to available preoperative scores (P = .0015). No intraoperative complications occurred during the 13 primary THAs.Conclusion: THA in patients with OI is associated with high revision rates and low survivorship at long-term follow-up. Although this is a very challenging patient population, THA provided these patients with improved functional outcomes. To the authors' knowledge, this is the largest series of primary THA in patients with OI reported in the literature and therefore provides surgeons with important data regarding the expected outcomes following THA in this unique patient population.Level Of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

Background: Unconstrained tripolar articulations have been theorized to increase hip stability. The purpose of this study is to report the performance of tripolar articulations in revision THA and identify factors associated with success and failure.Methods: Between 1994 and 2016, 67 revision THAs were performed with an unconstrained tripolar articulation. Mean follow-up was 5.4 years. Patient charts were retrospectively reviewed emphasizing factors associated with risk of instability. There were 21 patients with neither a history of instability (HI) nor abductor insufficiency (AI), 20 patients with HI alone, 13 with AI alone, and 13 had both HI and AI.Results: Twelve THAs sustained at least one postrevision dislocation at an average of 2.1 years. One bipolar dissociation occurred early (1.2 y). Nine hips had a re-revision to address these complications. Survival free from dislocation at 2, 5, and 10 years was 88%, 85%, and 74%, respectively. Survival free from re-revision at 2, 5, and 10 years was 91%, 84%, and 65%, respectively. Patients with combined AI and HI had the worst survivorship free from dislocation at 2, 5, and 10 years (77%, 68%, and 55%), respectively. In contrast, patients with neither HI nor AI experienced zero dislocations. There were no failures associated with bearing wear.Conclusion: Off-the-shelf tripolar articulations were associated with reasonable survival at midterm follow-up. In patients with both AI and HI, the risks and benefits of alternative options such as dual mobility or constrained liners should be explored as the risk of dislocation at 10 years approached 50%. [ABSTRACT FROM AUTHOR]

Background: Coronavirus disease 2019 (COVID-19) pandemic poses an important risk to global health.Methods: This study surveyed 370 international orthopedic surgeons affiliated with the American Association of Hip and Knee Surgeons to help identify the global impact of the COVID-19 pandemic on patient care.Results: A total of 99 surgeons (27% of those surveyed) completed the questionnaire representing 32 different countries. Except for surgeons in Japan, all respondents noted that their practice had been affected to some degree and 70% of the surgeons have canceled elective procedures. More than a third of the surgeons have had to close their practices altogether and the remaining open practices were estimated to be sustainable for 7 weeks on average given their current situation.Conclusion: The COVID-19 pandemic has resulted in marked changes to the majority of international arthroplasty practices. [ABSTRACT FROM AUTHOR]

Background: The aims of this study were to determine the levels of cobalt (Co) and chromium (Cr) ions generated in simulators from metal-on-polyethylene (MoP) and ceramic-on-polyethylene (CoP) constructs. Furthermore, we aimed to investigate the cytotoxic effect of these ion levels on native tissues and their potential to modify periprosthetic joint infection risk.Methods: We used in vitro culture of human adipose-derived mesenchymal stem cells (AMSCs) and Staphylococcus epidermidis cultures, respectively. Ten hip simulator constructs (5 MoP and 5 CoP) were assembled and run for 1,000,000 cycles in bovine serum and evaluated for CoCr concentration. Cytotoxicity and growth impact on AMSCs and S. epidermidis was compared between CoCr and inert silicon dioxide.Results: After 1,000,000 cycles, mean MoP and CoP Co concentration was 2264 and 0.6 ng/mL, respectively (P < .001). Mean MoP and CoP Cr concentration was 217 and 4.3 ng/mL, respectively (P < .001). Mean MoP Co:Cr ratio was 10:1. Co ions were significantly more toxic to human AMSCs than control silicon dioxide in a dose-response manner (P < .001). S. epidermidis growth was not significantly impacted by Co concentrations observed in the simulators.Conclusion: MoP constructs built in ideal conditions generated substantial CoCr debris, highlighting a baseline risk with these implants that may be exacerbated by host factors or imperfect surgical technique. Evaluation of impact on AMSCs suggests that debris levels produced under simulator conditions can be cytotoxic. In addition, these concentrations did not potentiate or inhibit S. epidermidis growth, suggesting that elevated periprosthetic joint infection rates with adverse local tissue reaction are related to other factors potentially associated with tissue necrosis. [ABSTRACT FROM AUTHOR]

Background: Few studies have described the outcomes following conversion of failed hemiarthroplasties to total hip arthroplasty (THA) and the impact of mortality when estimating implant survivorship. The aims of this study were to evaluate the following: (1) the risks and predictors of complications, dislocations, reoperations, and revisions and (2) the extent of competing risk of death when evaluating outcomes in patients converted from hemiarthroplasty to THA.Methods: The study comprised 389 patients treated with conversion THA following hemiarthroplasty for femoral neck fractures between 1985 and 2014. Revision rates were calculated using both the Kaplan-Meier method and cumulative incidence accounting for death as a competing risk. Risk factors were evaluated using Cox regression models.Results: During an average 9.3 years of follow-up, there were 122 complications, 34 dislocations, 69 reoperations, and 51 revisions. Conversion for periprosthetic fractures was associated with a higher risk of reoperations (hazard ratio 4.30, 95% confidence interval 1.94-9.52). Increasing age was a risk factor for reoperations (hazard ratio 1.32, 95% confidence interval 1.10-1.59). No decrease in the rate of complications, dislocations, reoperations, or revisions was observed over the entire 30 years of the study either when evaluating year of surgery as a continuous variable or when comparing specific calendar year intervals (1985-1989, 1990-1999, 2000-2009, 2010-2014) (P > .05). Compared to the cumulative incidence accounting for the competing risk of death, the Kaplan-Meier method overestimated the risk of revision by 7% at 15 years and 10% at 20 years.Conclusion: Conversion from hemiarthroplasty to THA remains at high risk for subsequent complications. The cumulative incidence estimate provides a more accurate estimate of revision risk. [ABSTRACT FROM AUTHOR]

Background: As revision implants and techniques have evolved and improved, understanding why contemporary revision total hip arthroplasties (THAs) fail is important to direct further improvement and innovation. As such, the goals of this study are to determine the implant survivorship of contemporary revision THAs, as well as the most common indications for re-revision.Methods: We retrospectively reviewed 2589 aseptic revision THAs completed at our academic institution between 2005 and 2015 through our total joint registry. Thirty-nine percent were isolated acetabular revisions, 22% isolated femoral revisions, 18% both component revisions, and 21% head/liner component exchanges. The mean age at index revision THA was 66 years, and 46% were male. The indications for the index revision THA were aseptic loosening (21% acetabular, 15% femoral, 5% both components), polyethylene wear and osteolysis (18%), instability (13%), fracture (11%), and other (17%). Mean follow-up was 6 years.Results: There were 211 re-revision THAs during the study period. The overall survivorship free of any re-revision at 2, 5, and 10 years was 94%, 92%, and 88%, respectively. The most common reasons for re-revision were hip instability (52%), peri-prosthetic fracture (11%), femoral aseptic loosening (11%), acetabular aseptic loosening (9%), infection (6%), polyethylene wear (3%), and other (8%).Conclusion: Compared to historical series, the 88% survivorship free of any re-revision at 10 years in a revision cohort at a referral center is notably improved. As implant fixation has improved, aseptic loosening has become much less common after revision THA, and instability has come to account for more than half of re-revisions. [ABSTRACT FROM AUTHOR]

Background: Unicompartmental knee arthroplasty (UKA) is commonly performed as an outpatient procedure. To facilitate this process, a single-dose intravenous (IV) perioperative antibiotic administration is required compared to 24-hour IV antibiotic dosing schedules that are typical of most inpatient arthroplasty procedures. There is a paucity of literature to guide surgeons on the safety of single-dose perioperative antibiotic administration for arthroplasty procedures, particularly those that will be performed in the outpatient setting. The purpose of this study is to evaluate a large series of UKA performed with single-dose vs 24-hour IV antibiotic coverage to determine the impact on risk for surgical site infection (SSI).Methods: All UKA cases were evaluated from 2007 to 2017 performed by a single surgeon at an academic institution. There were 296 UKAs in the cohort: 40 were outpatient procedures receiving single-dose antibiotics and 256 were inpatient procedures receiving 24-hour antibiotics. No patients were prescribed adjuvant oral antibiotics. Mean age was 64 years, 50% were female, mean body mass index was 32 kg/m2, and mean follow-up was 4.1 years (range 1.0-10.4). Perioperative antibiotic regimen was evaluated and SSI, defined as occurring within 1 year of surgery, was abstracted through a prospective total joint registry and manual chart review.Results: SSI occurred in 2 of 296 cases (0.7%) in the entire cohort, 2 of 256 inpatient UKAs (0.8%), and 0 of 40 outpatient UKAs (0%) (P = 1.00). One SSI was a deep infection occurring 6 weeks postoperatively that required 2-stage exchange and conversion to total knee arthroplasty. The other was a superficial infection treated with 2 weeks of oral antibiotics.Conclusion: This study demonstrates a low SSI risk (0.8% or less) following UKA with both single-dose and 24-hour IV antibiotics. Administering single-dose perioperative antibiotics is safe for UKA, which should alleviate that potential concern for outpatient surgery.Level Of Evidence: Level III, Therapeutic. [ABSTRACT FROM AUTHOR]

Background: There is a paucity of literature on contemporary aseptic revision total knee arthroplasty in patients ≤50 years. We sought to determine risk factors for failure in this population, with specific emphasis on survivorship free of (1) all-cause re-revision and (2) re-revision for instability.Methods: We retrospectively reviewed 135 nononcologic revision total knee arthroplasties (TKAs) performed from 2000 to 2012 in patients ≤50 years. Mean age was 43 years, and mean body mass index was 31 kg/m2. Mean follow-up was 7 years. There were 99 (73%) first-time revisions, and 36 (27%) with prior revisions. Indications for revision included instability (47%), aseptic loosening (29%), and arthrofibrosis (9%). Multivariate Cox regression analysis was used to identify risk factors.Results: Survivorship free of all-cause re-revision was 66% at 10 years, with multiply revised TKAs (hazard ratio [HR] = 2.6, P = .008) having the poorest survivorship. Forty-three (32%) TKAs underwent re-revision including 10 (7%) for periprosthetic joint infection. Survivorship free of re-revision for instability was 88% at 10 years, with revision for instability (HR = 19, P = .03), male gender (HR = 3.0, P = .05), and multiply revised TKAs (HR = 3.5, P = .03) having poorer survival. Of the 64 TKAs revised for instability, 24 (38%) underwent re-revision, including 14 (22%) for recurrent instability.Conclusion: Patients ≤50 years undergoing contemporary aseptic revision TKA had a 1 in 3 risk of re-revision. Patients specifically revised for instability or had prior TKA revisions had the highest risk of re-revision at 10 years.Level Of Evidence: IV. [ABSTRACT FROM AUTHOR]

Background: Constrained liners are used to treat recurring total hip arthroplasty dislocations in certain patients. Little is known about the fate of constrained liner revisions. The aim of this study is to evaluate the rate and survivorship free of revision for mechanical failure of constrained liners in patients who were revised to their first, second, and third constrained liners.Methods: From 1989 to 2016, using our institution's total joint registry, we identified 554 revisions to a first constrained liner. Of the 554, 40 had mechanical failure of their index constrained liner and had revision to a second constrained liner. Of the 40, 13 had mechanical failure of their second constrained liner and had revision to a third constrained liner. Patients included in the failure analysis had minimum 2-year follow-up, with a mean follow-up of 5.5 years.Results: In patients receiving their first, second, and third constrained liners, the survivorship free of revision for mechanical failure at 4 years was 90%, 52%, and 28%, respectively. Patients with a second and third constrained liner were more likely to have a revision for mechanical failure (second odds ratio 8, P < .0001; third odds ratio 10, P < .0001) compared to those receiving their first constrained liner. Using a different constrained liner did not decrease the risk of failure.Conclusion: After revision to a second or third constrained liner there is high rate of mechanical failure. When a total hip arthroplasty becomes unstable after constrained liner, surgeons should exercise caution before revising to another constrained liner. [ABSTRACT FROM AUTHOR]

Background: Klippel-Trénaunay syndrome (KTS) is a severe vascular malformation that can lead to hypertrophic osteoarthritis. Total knee arthroplasty (TKA) performed in extremities affected with KTS is challenging given the high-risk vascular considerations and occasionally poor bone quality.Methods: We identified 12 patients with KTS who underwent TKA between 1998 and 2017. There were 7 men, mean age 42 years, and mean follow-up was 7 years. Before arthroplasty, 2 patients (17%) had preoperative sclerotherapy. Preoperative vascular studies were done for 9 patients (75%) and included magnetic resonance imaging (n = 7), magnetic resonance angiography (n = 1), and computed tomography angiography (n = 1). A preoperative blood conservation protocol was used for all operations and included the use of tranexamic acid (TXA) in later years. Posterior-stabilized TKA was used in 10 cases and cruciate-retaining TKA was used in 2 cases.Results: At final follow-up, 2 patients (17%) had undergone revision surgery: 1 for infection and 1 for tibial loosening with subsequent arthrofibrosis. Knee Society Scores (36-83, P < .0001) and functional scores (48-84, P = .0007) significantly increased between the preoperative and postoperative period. Likewise at last follow-up, the mean knee range of motion significantly increased (82°-104°, P = .04). Median blood loss for patients who received TXA was 200 mL compared to 275 mL in patients who did not receive TXA (P = .66). Likewise there was no difference (P = .5) in the proportion of patients who required a transfusion between those who received TXA (2/6, 33%) and those who did not (3/6, 50%).Conclusion: In this small series, TKA can lead to significant clinical improvement for patients with KTS. Modern blood management techniques and a careful multidisciplinary care approach render TKA a reasonable option for select patients with KTS.Level Of Evidence: Level IV case series, therapeutic. [ABSTRACT FROM AUTHOR]

Background: Two-stage exchange for periprosthetic joint infection (PJI) in total knee arthroplasty (TKA) remains the gold standard treatment in North America. Occasionally, patients with knee PJI are referred for definitive management after resection and antibiotic spacer placement. Currently, little literature exists to suggest how these patients should be managed. The purpose of this study is to report the clinical outcomes of these patients.Methods: We retrospectively identified 54 patients (54 knees) from 2000 to 2012 treated for PJI with initial TKA resection and spacer placement performed somewhere other than the definitive treatment center. The mean age at reimplantation was 64 years, with 59% being male. Redebridement and antibiotic spacer exchange was performed for all patients. Mean follow-up was 6.5 years.Results: Of the 54 knees, 22 (41%) grew an organism from a culture taken at the time of redebridement and spacer exchange. The most common organism identified at redebridement was Staphylococcus aureus (41%). Obtaining positive cultures at redebridement was not associated with presenting erythrocyte sedimentation rate (P = .46), C-reactive protein (P = .57), or the presence of retained cement (P = .13). Forty-nine of 54 (91%) knees were ultimately reimplanted. Two-year survivorship free of infection in reimplanted knees was 98%.Conclusion: Patients referred with an antibiotic knee spacer for PJI have a high rate of positive cultures at the time of redebridement. Neither the presenting serology nor the identification of retained cement was associated with obtaining positive cultures at the time of redebridement. Nevertheless, this unique cohort of patients has favorable outcomes when redebrided with spacer exchange prior to reimplantation. [ABSTRACT FROM AUTHOR]

Background: Recurrent instability remains a challenge after revision total hip arthroplasty (THA). We report the outcomes of cementing a cementless dual mobility (DM) component into a stable acetabular shell for the treatment and/or prevention of instability in revision THA.Methods: Eighteen patients (18 THAs) undergoing revision THA with a specific monoblock DM construct cemented into a new acetabular component or an existing well-fixed component from 2011 to 2014 were retrospectively reviewed. Tumor prostheses and total femoral replacements were excluded. In 9 patients (50%), components were implanted specifically for recurrent dislocations. Mean age was 64 years; mean follow-up was 3 years. Patients underwent an average of 4 prior hip operations (range 2-6).Results: No cemented DM cups dissociated at the cement-cup interface. Three patients (17%) experienced a postoperative dislocation. One required a revision to constrained liner and 2 underwent open reduction with retention of the DM construct. Harris Hip Scores improved from 53 to 82 postoperatively (P < .001).Conclusion: Cementation of a monoblock cup DM construct, an off-label use as the construct is not specifically made for cementation, into a well-fixed acetabular component provides an alternative to enhance prosthetic stability in (1) recurrently dislocating THAs with well fixed, well-positioned acetabular components and (2) complex acetabular reconstructions in which constraint should be avoided. While not a perfect solution in this series, DM constructs provide a number of advantages including no added constraint at the interface and a large effective femoral head to diminish prosthetic impingement. [ABSTRACT FROM AUTHOR]

Purpose: To determine the contribution of the ligamentum teres (LT) to hip stability in the presence of an intact capsule with special attention to the change in range of motion and femoral head translation.Methods: Seven fresh-frozen cadaveric pelvises were used. Following visual inspection of the LT at different hip positions, internal rotation angles were measured at 10° of extension and at 0° of flexion, while external rotation was measured at 60°, 90°, and 110° of flexion with different hip abduction angles using electromagnetic motion tracking sensor. Femoral head translations were measured simultaneously. The tests were repeated after resection of the LT. The capsule was left intact for all test conditions. The results were compared between intact and LT resected conditions when torque of 2 and 4 Nm was applied.Results: Compared with the intact hip, the LT resected hip showed no significant difference when 2 Nm torque was applied in all scenarios. With 4 Nm torque application, significant increase in external rotation was found at 60° and at 90° of flexion (1.7° ± 0.8° and 2.1° ± 1.0°, respectively). Significant difference was also noted at 60°, 90°, and 110° of flexion when the hip was in the adducted position while at 90° in the abducted hip. However, LT resection did not show significant change in internal rotation. There was no significant difference in the translation distance of the femoral head in the intact hip compared with the LT resected hip (0.77-1.11 mm vs 0.79-1.29 mm).Conclusions: Our results indicate that within the physiologic range of motion, LT can minimally limit external rotation when the hip is in the flexed position but does not contribute to translation stability.Clinical Relevance: In the hip with intact capsule, LT deficiency can result in a slight increase in range of motion, but its contribution to stability is questionable. [ABSTRACT FROM AUTHOR]

Background: While studies have shown that postoperative wound complications can predispose to deep infection following orthopedic surgery, the best form of skin closure has not been elucidated. Furthermore, the unique risks and benefits of each type of wound closure have not been studied. The goal of this study is to present the diagnosis and treatment of patients with allergic contact dermatitis (ACD) from 2-octyl cyanoacrylate, a skin adhesive commonly used in wound closure.Methods: Twenty-nine patients with ACD to 2-octyl cyanoacrylate (Prineo, Ethicon, NJ) following elective orthopedic surgeries from 2013 to 2016 were retrospectively reviewed; this occurred in 29 of 6088 units of Prineo used at our institution, for an estimated incidence of 0.5%. Nineteen patients (66%) had knee operations. Mean age was 55 years (range, 15-92 years). We classified patients by symptom severity and treatment requirements into mild, moderate, and severe reactions.Results: Most reactions were moderate (48%) or severe (38%) reactions. Mean time from surgery to diagnosis was 11.8 days (range, 2-42 days). All patients underwent removal of the Prineo dressing and daily dressing changes with a specific protocol. Twenty patients (69%) received oral antihistamines, 16 patients (55%) required topical corticosteroids, and 5 patients (17%) required oral corticosteroids. All cases of ACD ultimately resolved at a mean of 22 days (range, 13-56 days) postoperatively.Conclusion: 2-Octyl cyanoacrylate skin adhesive occurs in an estimated 0.5% of cases and can lead to severe postoperative ACD when used following orthopedic operations. However, with early recognition and appropriate treatment, patients' symptoms resolve without a significant impact on wound healing. [ABSTRACT FROM AUTHOR]

Femoral impaction grafting is a utilitarian technique for femoral defects. With modern implants, its role may be limited to Paprosky 3B and 4 type femoral deficiencies, especially in the younger patient. With appropriate technique, mid- and long-term results have proven this technique to be globally reliable. Periprosthetic fracture is not uncommon with this technique; however, strategies to mitigate the risk have been developed. A thorough understanding of the history, technique, results and complications of this technique is essential for the revision hip surgeon in order to obtain successful results in the most complex femoral reconstruction cases. [ABSTRACT FROM AUTHOR]

The use of cemented femoral stem fixation has declined in North America despite numerous favorable long-term outcomes reported. Cemented stems offer some advantages over cementless fixation and should therefore remain part of every orthopaedic surgeon’s armamentarium. Long-term survival, versatility, low periprosthetic fracture risk, decreased risk of infection, and the cement within cement revision technique are all advantages of cemented fixation. Surgeons should be knowledgeable of different cemented stem designs including both the composite-beam and taper-slip philosophies, and must avoid mixing their principles in order to achieve durable clinical success. [ABSTRACT FROM AUTHOR]

Structural abnormalities of the hip including developmental dysplasia (DDH) and femoroacetabular impingement (FAI) are a predominant cause of primary osteoarthritis. While affected patients may have significant pain and functional limitations, many may remain asymptomatic and will likely incur intra-articular damage over time. The objective of this review is to explore the natural history of DDH, FAI, and the current outcomes of hip preservation surgery including peri-acetabular osteotomy, hip arthroscopy, and surgical hip dislocation. [ABSTRACT FROM AUTHOR]

Background: Revision total hip arthroplasty (THA) is challenging specially in the presence of severe acetabular bone deficiency. We report the use of a highly porous revision shell augmented by structural allograft to provide structural support and coverage to the acetabular component.Methods: We identified 56 patients (58 hips) undergoing revision THA, where a trabecular metal revision cup was supported by structural allograft. Mean follow-up was 5.4 years (range 2-12 years). Preoperatively acetabular bone defects were classified as Paprosky 2A in 6 hips (10%), 2B in 12 hips (21%), 2C in 12 hips (21%), 3A in 11 hips (19%), and 3B in 17 hips (29%). Structural allograft configuration was classified as type 1 (flying buttress) in 13 hips, type 2 (dome support) in 23 hips, and type 3 (footings) in 17 hips, with 5 hips having combined configurations.Results: All hips showed evidence of union between the allograft and host bone at latest follow-up, 14 hips had partial resorption of the allograft that did not affect cup stability. Three acetabular components demonstrated failure of ingrowth. Survivorship-free from radiographic acetabular loosening as end point was 94% at 5 years. The 5-year survivorship with revision for any reason as end point was 90%.Conclusion: Trabecular metal shells combined with structural bone allograft in revision THA demonstrate excellent midterm survival, with 94% of acetabular components obtaining stable union onto host bone at 5 years. Allograft restored bone stock with minimal resorption, and when it occurred did not alter the survivorship of the acetabular component. [ABSTRACT FROM AUTHOR]

Background: Prior studies comparing unicompartmental knee arthroplasty (UKA) with total knee arthroplasty (TKA) in the elderly are limited by heterogeneity in arthritic disease patterns and patient selection. We report the results of UKA and TKA in patients 75 years and older with isolated medial compartmental arthritis, with special emphasis on immediate postoperative recovery, complications, reoperation rates, and implant survivorship at midterm follow-up.Methods: A retrospective review was performed of all patients 75 years and older who underwent UKA or TKA at our institution between 2002 and 2012. All TKA preoperative X-rays were reviewed by a blind observer to identify knees with isolated medial compartmental arthritis considered acceptable candidates for UKA. Patients with less than 2 years of follow-up, flexion contracture greater than 10°, and rheumatoid arthritis were excluded. The final sample included 120 UKA (106 patients) and 188 TKA (170 patients) procedures. Patient records were reviewed to determine early postoperative recovery, complications, reoperations for any reason, and implant survivorship.Results: UKA patients experienced significantly shorter operative time, shorter hospital stay, lower intraoperative estimated blood loss, lower postoperative transfusions, greater postoperative range of motion, and higher level of activity at time of discharge. Two UKA and 2 TKA patients required revision surgery. There was no statistically significant difference in postoperative Knee Society Scores. There were no differences in 5-year survivorship estimates.Conclusion: Due to its less invasive nature, patients older than 75 undergoing UKA demonstrated faster initial recovery when compared to TKA, while maintaining comparable complications and midterm survivorship. UKA should be offered as an option in the elderly patient who fits the selection criteria for UKA. [ABSTRACT FROM AUTHOR]

Background: To resurface or not to resurface the patella remains a controversy in total knee arthroplasty (TKA). The purpose of this study was to assess the long-term outcomes associated with selectively not resurfacing the patella.Methods: This was a historical cohort study of 15,497 patients with 21,371 primary TKA procedures performed at a single institution between 1985 and 2010. The cohort included 402 (2%) knees with unresurfaced patellae and 20,969 knees with all-polyethylene patellae designs. Reasons for not resurfacing the patella were documented. Multivariable Cox regression analyses were used to estimate the risk of complications and revisions among procedures with unresurfaced patellae.Results: According to the surgeon, reasons for not resurfacing were normal cartilage (226, 56%), young patient (30, 8%), thin patella (53, 13%), and surgeons' choice (93, 23%). In age, sex, and calendar year-adjusted analyses, the risk of complications (hazard ratio [HR]: 1.25, 95% confidence interval [CI]: 1.06, 1.46) and all-cause revisions (HR: 1.39, 95% CI: 1.02, 1.89) were significantly higher after TKA with unresurfaced patellae. However, after adjusting for femoral component types and operative diagnoses, these associations were no longer significant. The only group with significantly worse outcomes were those with a thin patellae with increased risk of complications (HR: 2.66, 95% CI: 1.70, 4.17) and revisions (HR: 5.94, 95% CI: 2.35, 15.02). Yet, the excess risk in the thin patellae group was mainly due to infections, and not related to unresurfaced patellae.Conclusion: Selectively not resurfacing the patella seemed to provide similar results compared with routine resurfacing. [ABSTRACT FROM AUTHOR]

Background: The Exeter cemented femoral stem has demonstrated excellent clinical and radiographic outcomes as well as long-term survivorship free from aseptic loosening. A shorter revision stem (125 mm) with a 44 offset became available for the purpose of cement-in-cement revision situations. In certain cases, this shorter revision stem may be used for various primary total hip arthroplasties (THAs) where the standard length stem would require distally reaming the femoral canal. We sought to report on the early to midterm results of this specific stem when used for primary THA regarding (1) clinical and radiographic outcomes, (2) complications, and (3) survivorship.Methods: Twenty-nine patients (33 hips) underwent a hybrid THA using the smaller revision Exeter cemented femoral stem. Twenty-five patients (28 hips) had at least 2 years of follow-up and were assessed for clinical and radiographic outcomes. All 33 hips were included in the analysis of complications and survivorship. The Kaplan-Meier survivorship was performed using revision for all causes and for aseptic loosening as the end points.Results: The average clinical follow-up was 4 years (range, 2-7). Harris Hip Scores improved from a mean preoperative value of 56 (range, 23-96) to 90 (range, 51-100) at the latest follow-up. All patients demonstrated superior cement mantles with no signs of loosening. One patient suffered a B2 periprosthetic fracture and 1 patient experienced 2 episodes of instability. The 5-year Kaplan-Meier survivorship was 96.7% for all causes of revision and was 100% using aseptic loosening as the end point.Conclusion: The shorter Exeter revision cemented femoral stem has favorable early to midterm clinical and radiographic outcomes when used for primary THA with a low complication rate and is a viable option in patients with narrow femoral canals where uncemented stem fixation is not desired. [ABSTRACT FROM AUTHOR]

Background: Few studies have reported the results of total knee arthroplasty (TKA) in patients with previous patellectomy. The purpose of this study was to assess the risk of complications and survivorship of primary TKA in patients who previously had a patellectomy in comparison to those undergoing TKA with patellar resurfacing.Methods: This was a historical cohort study and comprised 134 knees with previous patellectomy in a cohort of 17,946 primary TKA procedures at a single institution between 1985 and 2010. Multivariable Cox regression analyses were used to estimate the risk of complications and revisions in patients with previous patellectomy.Results: When compared to TKA with patellar resurfacing, the risk of complications (hazards ratio: 1.38, 95% confidence interval: 1.05, 1.81) was significantly higher in post-patellectomy knees, but there was no difference in the risk of revisions (hazards ratio: 1.32, 95% confidence interval: 0.80, 2.18). There was no significant difference between the posterior-stabilized and cruciate-retaining designs in terms of both complications and revisions (P > .05). The most common complications in post-patellectomy knees were instability, delayed healing, and infection.Conclusion: TKA patients with previous patellectomy have a higher risk of complications but not a higher risk of revisions. [ABSTRACT FROM AUTHOR]

Background: Incompletely solved problems in hip and knee arthroplasty present ongoing practice challenges.Methods: Content experts summarized treatment options and preferred treatment methods for 4 incompletely solved problems in hip and knee arthroplasty.Results: The problems chosen for discussion in this symposium included 2 soft tissue problems: chronic extensor mechanism deficiency after total knee arthroplasty and abductor deficiency after total hip arthroplasty (THA), recurrent infection after a 2-stage procedure for infected THA or total knee arthroplasties, and pelvic discontinuity after THA.Conclusion: The approaches outlined may provide guidance on management of these different problems. For surgeons and others in the orthopedic community interested in innovation, these challenges also present ripe opportunities to improve the care of patients with unmet needs. [ABSTRACT FROM AUTHOR]

Background: The primary purpose of our study was to determine the prevalence of Cam deformity in patients with symptomatic acetabular dysplasia (SAD) who underwent periacetabular osteotomy (PAO).Methods: We retrospectively reviewed 164 SAD PAO patients from 2 institutions. Preoperative anteroposterior and frog-lateral radiographs were analyzed for lateral center edge angle (LCEA), retroversion, alpha angles, and anterior femoral head-neck offset. Hips were classified as dysplastic (LCEA <20°, group A, n = 142) and borderline dysplastic (LCEA 20°-25°, group B, n = 22). There were 128 females and 36 males with an average age of 29 years (range 13-56).Results: The overall prevalence of Cam deformity was 10% (17 of 164) in SAD patients. There was no difference in the prevalence of Cam deformity between the groups (P > .99).Conclusion: Prevalence of Cam deformities in our series of SAD patients having undergone PAO is less than prior reports. Careful radiographic measurement should be performed to avoid overtreating these hips with unnecessary osteochondroplasty procedures. [ABSTRACT FROM AUTHOR]

Background: Addressing recurrent instability in patients with poor bone stock and inadequate abductor tensioning remains a challenge in revision total hip arthroplasty. One treatment method is implantation of a constrained liner. The purpose of this study was to determine clinical outcomes, redislocation rate, and revisions of a focally constrained liner in a high-risk patient cohort.Methods: Fifty-eight hips between 2008 and 2011 underwent implantation of a focally constrained liner. Nineteen were placed concurrent with acetabular component revision and 39 were placed into a well-fixed acetabular shell. Mean age was 69 years and mean number of previous ipsilateral hip surgeries was 4.2. At mean follow-up of 3.5 years, we analyzed clinical outcomes, redislocation, and revisions.Results: Mean Harris Hip Scores was 74. Fourteen hips (24%) were revised and 3 hips (5%) required reoperation at final follow-up. Eleven hips (19%) redislocated at a mean time to dislocation of 12.2 months; 31% (11 of 36 patients) that underwent modular exchange specifically for instability redislocated. Risk factors for redislocation included number of previous surgeries (P = .013), implantation of a 28 mm femoral head (hazards ratio 12.8), revision indication of instability (P = .04), and modular exchange with constrained liner implantation without acetabular shell revision (P = .01).Conclusion: Implantation of a focally constrained liner in revision total hip arthroplasty for recurrent instability has a high failure rate, especially with a modular exchange. Although concurrent acetabular revision had a lower redislocation rate, the decision to revise a well-fixed cup should be weighed with potential complications associated with cup revision. [ABSTRACT FROM AUTHOR]

Background: Open and arthroscopic approaches have been described to address femoroacetabular impingement (FAI). Despite good outcomes, there is a subset of patients who subsequently require total hip arthroplasty (THA). However, there is a paucity of data on the outcomes of THA after surgery for FAI. The purpose of this study was to determine whether clinical outcomes of THA are affected by prior open or arthroscopic treatment of FAI.Methods: This case-matched retrospective review included 23 patients (24 hips) that underwent THA after previous surgery for FAI (14 arthroscopic and 10 open) and compared them to 24 matched controls with no history of prior surgery on the operative hip. The controls were matched for age, sex, surgical approach, implants used, and preoperative modified Harris hip score (mHHS) did not differ between groups. The primary outcome measure was the mHHS. Operative time, blood loss, and the presence of heterotopic ossification after THA were also compared between groups.Results: There was no significant difference in mean mHHS between the FAI treatment group 92.9 ± 12.7 and controls 95.2 ± 6.6 (P = .43) at a mean follow-up after THA of 33 (24-70) months. Increased operative times were noted for THA after surgical hip dislocation (SHD; mean 109.3 ± 29.8) compared to controls (mean 88.0 ± 24.2; P < .05). There was no significant difference in blood loss between groups. The occurrence of heterotopic ossification was significantly higher after SHD compared to controls (P < .05).Conclusions: Clinical outcomes after THA are not affected by prior open or arthroscopic procedures for FAI. However, increased operative times and an increased risk of heterotopic ossification were noted after SHD. [ABSTRACT FROM AUTHOR]

Background: It is unclear whether a positive skin patch test for metal allergy in patients with skin hypersensitivity to metals is associated with an increased risk of total knee arthroplasty (TKA) failure. Our aim was to determine whether patients with a history of metal allergy who had a positive skin patch test (SPT+) had worse outcomes after primary TKA compared with those with a negative skin patch test and compared with controls.Methods: Over 12 years, 127 patients underwent 161 TKA after skin patch testing (SPT; 56 were positive). Cases were matched by age, gender, body mass index, American Society of Anesthesiologists score, implant type, and implant manufacturer to 161 control knee arthroplasties without any prior history of metal allergy and no SPT. Median follow-up was 5.3 years. Differences in outcome measures were assessed between groups.Results: Patients with a SPT+ to metal did not have a higher complication, reoperation, or revision rates compared with patients with a SPT- and matched controls. Survivorship free of revision at 5 years was 98.1% for SPT+; 100% for SPT-; 97.6% for SPT+ controls, 99.0% for SPT- controls. There was no statistically significant difference in postoperative pain between SPT+ and SPT- patients and matched controls.Conclusion: This study was designed to evaluate the effect of metal hypersensitivity on TKA outcomes and the role of SPT in patients before TKA. In this study, a SPT+ for metals was of little practical value in predicting the midterm outcome after TKA and cannot be strongly recommended as a method to guide the selection of implant type. [ABSTRACT FROM AUTHOR]

Background: Pelvic discontinuity (PD) is a rare but devastating mechanism of failure in total hip arthroplasty. Radiographic findings have been described for the identification of PD. However, no study has specifically examined radiographic parameters and the utility of specific views in the preoperative identification of PD. Methods: We performed a retrospective review of 133 patients who underwent acetabular revision for PD. Preoperative radiographic studies were reviewed including anteroposterior pelvis (AP; n = 133), true lateral hip (n = 132), Judet (n = 47), false profile (n = 4), and computed tomography scans (n = 14). Radiographs were read by the senior authors to identify the following parameters suggestive of PD: visible fracture line, medial migration of the inferior hemipelvis, and obturator ring asymmetry. Results: Using only the AP view, the fracture line was visible in 116 (87%), medial migration of the inferior hemipelvis in 126 (95%), and obturator ring asymmetry in 114 (86%). A fracture line was visualized in 65 of 132 hips (49%) evaluated with laterals, 36 of 47 hips (77%) evaluated with Judet views, 3 of 4 (75%) evaluated with a false profile view, and 10 of 14 (71%) evaluated with computed tomography. Conclusion: Preoperative evaluation with a combination of an AP pelvis radiograph, plus a true lateral radiograph of the hip, plus Judet films in combination with the criteria for discontinuity defined in this article, allowed for identification of PD in a 100% of patients. [ABSTRACT FROM AUTHOR]

Background: Osteonecrosis (ON) of the femoral head occurs when cells of trabecular bone spontaneously die. Mesenchymal stem cells (MSCs) have been introduced into the femoral head in an attempt to halt progression of the disease. The purpose of this study was to functionally compare MSCs in patients with ON of the femoral head with patients without.Methods: Mesenchymal stem cells were isolated from 20 patients with corticosteroid-induced ON and 10 controls without. Colony-forming unit and proliferation assays were used to assess MSC proliferation. Mesenchymal stem cells were differentiated into bone, fat, and cartilage. Functional assays were used to quantify the differentiation capacity.Results: Control MSCs demonstrated greater cellular growth potential and improved ability to differentiate into bone.Conclusion: The decreased ability to differentiate into bone may be a reason why patients treated with autologous MSC infusion fail regenerative treatment strategies and progress to collapse. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to calculate the cumulative risk of periprosthetic joint infection (PJI) after aseptic index knee revisions and to identify the surgical, perioperative, and medical comorbidity risk factors associated with deep infection.Methods: We retrospectively reviewed 1802 aseptic index revision total knee arthroplasties performed at our institution from 1970 to 2000. From this cohort, there were 60 reoperations performed for deep infection.Results: The cumulative risk of infection at 1, 5, 10, and 20 years after index revision was 1%, 2.4%, 3.3%, and 5.6%, respectively.Conclusions: Male gender, use of constrained implants, increased operative times, increased Charlson Comorbidity Index, and a history of liver disease were all significantly associated with PJI. The development of cardiovascular disease, endocrine disorders, and renal disease were also associated with PJI. [ABSTRACT FROM AUTHOR]

Small studies have shown that patients who undergo TKA following a distal femur and/or tibial plateau fracture have inferior results. The purpose of this study was to evaluate the mid-term outcomes of a large group of patients undergoing TKA following periarticular knee fractures. We identified 531 patients who underwent a TKA following a periarticular fracture from 1990 to 2012; comparing outcomes to 19,641 patients undergoing primary TKA for osteoarthritis. Periarticular fracture significantly increased the risk of revision TKA, infection and complications. There was no difference in the need for revision TKA or infection based on fracture location. Patients with TKA following a periarticular fracture have worse overall revision free survival compared to with OA, with 1 in 4 patients requiring revision TKA by 15 years. [ABSTRACT FROM AUTHOR]

While tranexamic acid (TXA) reduces transfusion in total joint arthroplasty (TJA), it remains unclear whether there is a preoperative hemoglobin (Hgb) threshold above which it is no longer beneficial. 2100 primary TJA patients were retrospectively categorized by preoperative Hgb; 1161 (55%) received TXA. Transfusion rates decreased with TXA in all groups; with Hgb>15 the transfusion rate was 0.5% with TXA and 4.5% without (P=0.0086); with Hgb>11 the transfusion rate was 4.7% with TXA and 18.7% without (P<0.0001). Patients receiving TXA had a shorter LOS by 0.51 days (P<0.0001). Patients receiving a postoperative transfusion had a longer LOS by 0.69 days (P<0.0001). TXA should be considered in all TJA patients independent of preoperative Hgb level. [ABSTRACT FROM AUTHOR]

A retrospective analysis was conducted on 539 hips undergoing revision total hip arthroplasty done for instability to report the cumulative risk and factors associated with re-dislocation and re-revision. The cumulative risk of re-dislocation and re-revision for all cause was 34.5% and 45.9% at 15 years, respectively. Multiple variable analyses revealed history of 2 or more previous surgeries, use of head size less than 36 mm, and cup retention to be risk factors for re-dislocation and re-revision. The use of a constrained liner was protective against re-dislocation but was not associated with a lower re-revision rate. Understanding the risk factors associated with re-dislocation or re-revision may help with perioperative decision making in order to decrease the high failure rate seen in this study. [ABSTRACT FROM AUTHOR]

Femoral reconstruction in the setting of two stage reimplantation can be difficult and substantial reoperation rates due to implant loosening have been reported. We retrospectively reviewed 28 male and 29 female patients who underwent a two-stage reimplantation using a modular, tapered femoral stem. The mean clinical follow-up was 62 months. The mean Harris Hip score at 5-year follow-up was 76. Two stems were revised for aseptic loosening. Reinfection occurred in 16% of patients. Stem survivorship was 87% at 5-years. Use of a modular tapered stem provided a high rate of stable femoral fixation and acceptable rate of reinfection in two stage treatment of infected THA. [ABSTRACT FROM AUTHOR]

Objectives Cobalt (Co) exposure has been documented to result in increased erythropoiesis. To evaluate the potential for implant-derived Co toxicity, we examined the relationship between serum Co (sCo) and erythrocyte counts (ERY) in a metal-containing total-hip arthroplasty implant population. Methods Retrospective review of sCo concentrations identified 77 patients with concomitant ERY. Statistical analysis was performed to determine if there was a significant difference in ERY for patients divided into clinically relevant sCo ranges. A single detailed case review of a patient with a loose mal-positioned acetabular component and significantly elevated sCo was also performed for symptoms thought to arise from Co toxicity. Results Statistical difference in ERY was not observed between patients with significantly elevated (> 10 ng/mL), elevated (4–10 ng/mL), modestly elevated (1.0–3.9 ng/mL), or normal (< 1.0 ng/mL) sCo. While the detailed case report was unremarkable for any of the clinical symptoms previously reported to be associated with Co toxicity and no increase in ERY was observed, this patient's sCo was 84 ng/mL. Conclusions Increased erythropoiesis was not observed in patients with implant-derived increased sCo. Even with a sCo 100× the upper-limit of normal, the patient presented did not have increased ERY nor exhibit any symptoms ascribed with Co toxicity. [ABSTRACT FROM AUTHOR]

TKA and THA are associated with blood transfusion and risk for postoperative venothromboembolism (VTE). Reports show that tranexamic acid (TA) may be safe to use in high-risk orthopedic patients, but further data are needed to substantiate its use. All patients who underwent primary or revision TKA or THA in a five year period were retrospectively identified. In 13,262 elective TKA or THA procedures, neither the odds of VTE (OR = 0.98; 95% CI 0.67-1.45; P = 0.939) or adjusted odds of death (OR = 0.26; 95% CI 0.04-1.80; P = 0.171) were significant with TA administration. The major findings of this large, single center, retrospective cohort study show the odds of postoperative VTE and 30-day mortality were unchanged with TA administration. [ABSTRACT FROM AUTHOR]